 In 1834, he left to study at Andover Theological Seminary, but departed in 1836 after the college rejected agents from the American Anti-Slavery Society.Blanchard joined the group as one of Theodore Dwight Weld's "seventy" and preached in favor of abolition in southern Pennsylvania.Blanchard graduated from Lane Seminary in 1838 and was soon ordained to preach at Sixth Presbyterian Church in Cincinnati, Ohio.